This invention relates to an integrated circuit package having one or more lead-frame leads serving both as a ground lead and heat sink means, and more particularly pertains to such a package in which the one or more leads are an extension of and thus are connected to the die-attach pad and are connected electrically via a wire to a terminal on the top die surface.
In packages of the prior art, especially those at the heart of which is an integrated circuit die including logic and power devices, it is known to provide a terminal on the top surface of the die that is connected electrically via a fine gold wire to one lead of a lead frame, wherein that lead extends directly from the die support pad of the lead frame. That one lead will be able to conduct heat from the bottom of the die to the printed wire board circuitry to which that lead would normally be attached by soldering and the like, and thus the lead serves the dual purpose of removing heat and also providing an electrical connection to the terminal at the top of the die. A molded resin body encapsulates the die, the proximal end of all of the lead-frame leads, and all of the fine wire connections between die and proximal ends of the leads.
The fine wire lead from the above-mentioned die terminal connects the terminal either directly to a part of the die-attach pad itself or to the end of a lead-frame finger which extends from the die attach pad to a point that is positioned in line with the proximal ends of the other leads so that all wire-to-lead attach points are in a straight line making the wire bonding task less difficult.
It is an object of this invention to provide an integrated circuit lead-frame package having one or more simple low resistance ground-lead and heat-sink means and having a high tolerance to repeated temperature cycling.